<template>
  <div class="upload-file">
    <el-upload multiple :action="uploadFileUrl" :before-upload="handleBeforeUpload" :file-list="fileList" :limit="limit"
      :on-error="handleUploadError" :on-exceed="handleExceed" :on-success="handleUploadSuccess" :show-file-list="false"
      class="upload-file-uploader" ref="fileUpload">
      <!-- 上传按钮 -->
      <el-button size="mini" type="primary">选取文件</el-button>
      <!-- 上传提示 -->
      <div class="el-upload__tip" slot="tip" v-if="showTip">
        请上传
        <template v-if="fileSize">
          大小不超过 <b style="color: #f56c6c">{{ fileSize }}MB</b>
        </template>
        <template v-if="fileType">
          格式为 <b style="color: #f56c6c">{{ fileType.join('/') }}</b>
        </template>
        的文件
      </div>
    </el-upload>

    <!-- 文件列表 -->
    <transition-group class="upload-file-list el-upload-list el-upload-list--text" name="el-fade-in-linear" tag="ul">
      <li :key="file.url" class="el-upload-list__item ele-upload-list__item-content" v-for="(file, index) in fileList">
        <el-link :href="`${baseUrl}${file.url}`" :underline="false" target="_blank">
          <span class="el-icon-document"> {{ getFileName(file.url) }} </span>
        </el-link>
        <div class="ele-upload-list__item-content-action">
          <el-link :underline="false" @click="handleDelete(index)" type="danger">删除</el-link>
        </div>
      </li>
    </transition-group>
  </div>
</template>

<script>
  export default {
    name: 'FileUpload',
    props: {
      // 值
      value: [String, Object, Array],
      // 数量限制
      limit: {
        type: Number,
        default: 5,
      },
      // 大小限制(MB)
      fileSize: {
        type: Number,
        default: 50,
      },
      // 文件类型, 例如['png', 'jpg', 'jpeg']
      fileType: {
        type: Array,
        default: () => ['doc', 'xls', 'ppt', 'txt', 'pdf', 'mp4'],
      },
      // 是否显示提示
      isShowTip: {
        type: Boolean,
        default: true,
      },
    },
    data() {
      return {
        number: 0,
        uploadList: [],
        baseUrl: process.env.VUE_APP_BASE_API,
        uploadFileUrl: process.env.VUE_APP_BASE_API + '/home/file/upload', // 上传文件服务器地址
        fileList: [],
      };
    },
    watch: {
      value: {
        handler(val) {
          if (val) {
            let temp = 1;
            // 首先将值转为数组
            const list = Array.isArray(val) ? val : this.value.split(',');
            // 然后将数组转为对象数组
            this.fileList = list.map((item) => {
              if (typeof item === 'string') {
                item = { name: this.getFileName(item), url: item };
              }
              item.uid = item.uid || new Date().getTime() + temp++;
              return item;
            });
          } else {
            this.fileList = [];
            return [];
          }
        },
        deep: true,
        immediate: true,
      },
    },
    computed: {
      // 是否显示提示
      showTip() {
        return this.isShowTip && (this.fileType || this.fileSize);
      },
    },
    methods: {
      // 上传前校检格式和大小
      handleBeforeUpload(file) {
        // 校检文件类型
        if (this.fileType) {
          const fileName = file.name.split('.');
          const fileExt = fileName[fileName.length - 1];
          const isTypeOk = this.fileType.indexOf(fileExt) >= 0;
          if (!isTypeOk) {
            this.$message.error(`文件格式不正确, 请上传${this.fileType.join('/')}格式文件!`);
            return false;
          }
        }
        // 校检文件大小
        if (this.fileSize) {
          const isLt = file.size / 1024 / 1024 < this.fileSize;
          if (!isLt) {
            this.$message.error(`上传文件大小不能超过 ${this.fileSize} MB!`);
            return false;
          }
        }
        // this.$modal.loading("正在上传文件，请稍候...");
        this.number++;
        return true;
      },
      // 文件个数超出
      handleExceed() {
        this.$message.error(`上传文件数量不能超过 ${this.limit} 个!`);
      },
      // 上传失败
      handleUploadError(err) {
        this.$message.error('上传文件失败，请重试');
      },
      // 上传成功回调
      handleUploadSuccess(res, file) {
        if (res.code === 0) {
          this.uploadList.push({ name: res.fileInfo.fileName, url: res.fileInfo.filePath });
          this.uploadedSuccessfully();
        } else {
          this.number--;
          this.$message.error(res.msg);
          this.$refs.fileUpload.handleRemove(file);
          this.uploadedSuccessfully();
        }
      },
      // 删除文件
      handleDelete(index) {
        this.fileList.splice(index, 1);
        this.$emit('input', this.listToString(this.fileList));
      },
      // 上传结束处理
      uploadedSuccessfully() {
        if (this.number > 0 && this.uploadList.length === this.number) {
          this.fileList = this.fileList.concat(this.uploadList);
          this.uploadList = [];
          this.number = 0;
          this.$emit('input', this.listToString(this.fileList));
        }
      },
      // 获取文件名称
      getFileName(name) {
        // 如果是url那么取最后的名字 如果不是直接返回
        if (name.lastIndexOf('/') > -1) {
          return name.slice(name.lastIndexOf('/') + 1);
        } else {
          return name;
        }
      },
      // 对象转成指定字符串分隔
      listToString(list, separator) {
        let strs = '';
        separator = separator || ',';
        for (let i in list) {
          strs += list[i].url + separator;
        }
        return strs != '' ? strs.substr(0, strs.length - 1) : '';
      },
    },
  };
</script>

<style>
  .upload-file-uploader {
    margin-bottom: 5px;
  }

  .upload-file-list .el-upload-list__item {
    border: 1px solid #e4e7ed;
    line-height: 2;
    margin-bottom: 10px;
    position: relative;
  }

  .upload-file-list .ele-upload-list__item-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: inherit;
  }

  .ele-upload-list__item-content-action .el-link {
    margin-right: 10px;
  }
</style>